HRP920669A2 - Aqueous, stable suspensions of water insoluble silicates which are able to bind calcium ions and their use in the production of washing and cleaning agents - Google Patents

Abstract

Aqueous suspensions of a silicate capable of binding calcium ions, containing, based on the total weight of the suspension, a) as silicate, a compound corresponding to Formula I: (Cat2/nO)x*Me2O3*(SiO2)y(I) and B) as dispersing component, a mixture of at least two oxoalcohol ethoxylates corresponding to Formula II R-(OCH2CH2)n-OH(II), wherein R=C10-C15 alkyl having a degree of branching of 0 to 90% linear and 100 to 10% single methyl branches n=3-5.25 mol ethoxy groups in Component 1 n=5.5-7.0 mol ethoxy groups in Component 2 C) a polyethylene glycol having an average molecular weight of from 200 to 2000.

Description

It is known that for the washing and cleaning of solid materials, especially textiles, washing and cleaning agents are used, in which the role of binding the calcium complex is taken over by phosphites, completely or partially, aluminum silicates very finely dispersed in water, insoluble in water, capable of binding of calcium, which generally contain bound water (see DE-OS 24 12 837).

These are compounds of the general formula I:

(Kat2/nO)x⋅Me2O3⋅(SiO2)y (I),

in which Kat denotes a calcium exchangeable cation of value n, x is a number from 0.7 to 1.5 Me aluminum, and y is a number from 0.8 to 6, preferably from 1.3 to 4.

The most common cation is sodium, but it can be replaced by lithium, potassium, ammonium or magnesium.

The compounds defined above, capable of binding calcium, will be called "aluminum silicates" in the following text for the sake of simplification. This is especially true for primarily applicable sodium aluminum silicates: all data given for their application according to the invention and all data on their production and properties apply to all compounds defined above.

Aluminum silicates are particularly suitable for use in washing and cleaning agents, they have the ability to bind calcium from 50 to 200 mg CaO/g of anhydrous aluminum silicate.

When anhydrous aluminum silicate is mentioned in the future, it will be considered the condition of aluminum silicates that is achieved by drying at 800°C for 1 hour. During such drying, both free and bound water are completely removed.

In the production of washing and cleaning agents, in which, in addition to the usual ingredients of such agents, there are also aluminum silicates, as defined above, the starting point is primarily wet aluminum silicates, for example, such as those of the previously mentioned production. In doing so, the wet ingredients are mixed with at least a part of the other ingredients of the material to be produced and the mixture is subjected to known processes, such as spray drying, to obtain the final product in the form of a washing or cleaning agent, e.g. in a form suitable for pouring. . As part of the previously described production process for washing and cleaning agents, aluminum silicates are obtained or used in the form of an aqueous suspension. In doing so, certain improvements in the properties of suspensions of aluminum silicates dispersed in the aqueous phase were desired - for example, stability of the suspension and suitability for pumping.

It is known that alkylphenolethylene adducts (DE-A 26 15 698) are used to create suspensions of aluminum silicates. On the basis of increased environmental awareness, special attention is paid to the ability of biological decomposition.

The use of nonylphenol ethoxylate is known from DE-A 32 09 631. On the basis of their benzene ring, these compounds are considered difficult to degrade, where there is a particular danger of the formation of toxic nonylphenol as a metastable degradation product. Therefore, the German industry abandoned the use of nonylphenoloxylate in the production of washing and cleaning agents.

The use of iso-tridecyl alcohol oxylate is known from DE-A 34 44 311. At the same time, we are dealing with branched chain alcohols, with a branching percentage of at least 50%; countless mixtures of isomers, often with all possible branches such as methyl, ethyl, propyl, iso-propyl, etc.

From DE-A 37 19 042 the use of a mixture of two oxoalcohol-ethoxylates of the gormula R-(OCH2)n-OH is known. At high concentrations, unfortunately too high a viscosity is achieved here at room temperatures.

The subject of the invention is an aqueous, stable suspension of silicate insoluble in water, capable of binding calcium ions, which can be pumped, and which is characterized by the fact that it is reduced to the total mass of the aqueous suspension

A) as a silicate capable of binding calcium contains 0.5 to 80% by weight. finely dispersed, synthetically produced water-bound compound, according to the general formula I

(Kat2/nO)x·Me2O3·(SiO2)y (I),

in which Kat denotes a cation of value n, exchangeable with calcium, x is a number from 0.7 to 1.5, Me is boron or aluminum, and y is a number from 0.5 to 6, and

B) a mixture of at least two oxoalcohol-ethoxylates of formula II is used as a dispersing ingredient

R-(OCH2CH2)n-OH (II),

where R = C10-C15 alkyl with a degree of branching from 0 to 90% linear and 100 to 10% monobranched with methyl, where

n = 3 - 5.25 mol EO in component 1,

n = 5.5 - 7.0 moles of EO at component 2, i

C) one polyethylene glycol with an average molecular weight of 200 to 2000, whereby the mass fraction of components B and C, reduced to a suspension, is from 0.5 to 6, preferably from 1 to 2 wt. %, and especially from 1.4 to 1.6 wt. %.

In the suspension according to the invention, component A can be in crystalline form.

In formula I, the number y of component A can be from 1.3 to 4.

The crystalline component A can preferably be a type A zeolite.

The aforementioned compounds are essential ingredients of the suspension according to the invention. The suspension according to the invention may also contain other ingredients, such as additives to suppress the formation of foam, i.e. agents to improve dissolution, which improve the solubility of the added dispersing agents in the aqueous phase. The antifoam additives may be conventional antifoam agents, eg, antifoam soap, silicone antifoam, antifoam triazine derivatives, all of which are known and practiced in the art. Such an addition is generally not necessary; however, with foaming dispersants - especially higher alkylbenzene sulfonic acids - it may be desirable.

Also, the addition of substances to improve dissolution is generally not necessary, however, it may be indicated when the suspension according to the invention contains a hydrophilic, but poorly water-soluble colloid, such as polyvinyl alcohol, as a stabilizer. It is advantageous to use, for example, one solvent - such as sodium toluenesulfonate.

The proportion of the dissolution enhancer in the total suspension can be, for example, of the same order of magnitude as the proportion of the stabilizer. Further compounds suitable as dissolution enhancers are known to those skilled in the art; hydrophobic agents such as benzosulfonic acid, xylenesulfonic acid, or their salts or also octylsulfate are suitable.

All statements about "concentration of aluminum silicates", about "content of solid matter" or about the content of "active substance" (= AS) refer to the state of aluminum silicates, which is achieved after drying for one hour at 800°C. During such drying, practically all adhesive and bound water is completely removed.

Component A can be amorphous or crystalline products, and mixtures of amorphous and crystalline, as well as partially crystalline products can, of course, be used. Aluminum silicates can, of course, be from natural sources or produced synthetically, with synthetically produced having an advantage. Production can be carried out, for example, by reacting water-soluble silicates with water-soluble aluminates in the presence of water. For this purpose, aqueous solutions of starting materials can be mixed with each other, or one component, in a solid state, can be mixed with another, which is in an aqueous solution.

Also, by mixing both components in a solid state, in the presence of water, the desired aluminum silicates are obtained. Also, aluminum silicates can be produced from Al(OH)3, Al2O3 or SiO2 by reaction with alkali silicate or aluminate solution. Production can also be carried out according to other known procedures. The invention particularly relates to aluminum silicates, which have a three-dimensional spatial lattice structure.

The desired calcium binding properties, which lie in the range of 100 to 200 mg CaO/g, and most often between approximately 100 to 180 mg CaO/g AS, are obtained primarily with compounds of the composition:

0.7 - 1.1 Na2O⋅Al2O3⋅1, 3 - 3.3 SiO2

This summary formula includes two types of different crystal structures (that is, their non-crystallized precursors), which also differ in their summary formulas. These are:

a) 0.7 - 1.1 Na2O⋅Al2O3⋅1.3-2.4 SiO2

b) 0.7 - 1.1 Na2O⋅Al2O3⋅2.4 -3.3 SiO2

Differences in the crystal structure can be seen on X-ray diffraction images.

The aqueous suspension of the existing amorphous or crystalline aluminum silicate can be separated by filtration from the remaining aqueous solution and dried at a temperature of, for example, 50 to 400°C. Depending on the drying conditions, the product contains more or less bound water. Such high drying temperatures are generally not recommended; when aluminum silicate is intended for use in washing and cleaning agents, it is advisable not to go above 200°C.

However, aluminum silicates do not need to be dried at all after production for production according to the invention; even more - and this is of particular advantage - aluminum silicate can be used while it is still wet from production. Aluminum silicates dried at medium temperatures, for example at 80 to 200°C, can also be used for the production of suspension, until the adhesive water is removed.

The particle size of individual aluminum silicate particles can be different and can be, for example, in the range from 0.1 μm to 0.1 mm. Of particular advantage is the use of aluminum silicates, which consist of at least 80% by weight. particle size from 10 to 0.01 μm. It is advantageous that these aluminum silicates do not contain primary or secondary particles with a diameter greater than 45 μm. Secondary particles mean larger particles, created by the aggregation of primary particles.

Regarding the agglomeration of primary particles into larger formations, the use of aluminum silicates that are still wet from production in order to produce the suspension according to the invention has proven to be particularly good, because it has been shown that when using these, still wet products, the formation of agglomeration is practically completely prevented.

In one particularly suitable form of embodiment of the invention, powdered zeolite type A with a specially defined spectrum of particles can be used as A auxiliary component.

Such powdered zeolites can be produced according to DE-AS 24 47 021, DE-AS 25 17 218, DE-OS 26 52 419, DE-OS 26 51 420, DE-OS 26 51 436, DE-OS 26 51 437, DE -OS 26 51 445, DE-OS 26 51 485. They then have given particle distribution curves.

In one particularly suitable embodiment, zeolite type A can be used, which has a particle size distribution in accordance with that described in DE-OS 26 51 485.

The concentration of component A should be above all 44 to 55 wt %, especially 46 to 52 wt. % and more.

Component B can, first of all, consist of a mixture of two oxoalcohol-ethoxylates, whereby one component should contain one oxoalcohol-ethoxylate with 3 to 5.25 moles of ethylene oxide and have a cloud point at 56 - 68.5°C, preferably with 4 - 5 moles of EO and a cloud point at 60 - 67°C, whereby the carbon ring R has 10 - 15, preferably 12 - 13 C-atoms, and the second (B) component should be an oxoalcohol-ethoxylate with 5.5 to 7 ,0 moles of ethylene oxide and with a cloud point at 70.5 to 80°C, preferably 5.75 - 6.5 moles of EO and a cloud point at 71 -77°C, whereby the carbon ring R has 10 - 15, preferably 12 - 13 C-atom.

Oxalcohol-ethoxylates can be mixed in a ratio of 9:1 to 1:9, preferably 2:3 to 3:2, especially 0.9 to 1.1 to 1.1:0.9.

The concentration of components B and C in the aqueous solution can preferably be from 1 to 2 wt. %, especially 1.4 to 1.6 wt. %. This concentration is sufficient to stabilize the suspension with a solid content of 50 wt. % and more.

Component C (reduced to the amount of stabilizer consisting of components B and C) can be changed with a proportion of 3 to 20 wt. %, preferably from 5 to 15 wt. %. In one particularly suitable embodiment, the average molecular weight of polyethylene glycol can be 200 to 1000.

The suspension according to the invention also has the advantage that below 25°C it is stable in terms of precipitation and has a consistency suitable for pumping.

A further advantage is that the oxoalcohol ethoxylate is liquid at room temperature and therefore must be heated.

A special advantage is that with the suspension according to the invention, significantly higher percentages of solids of 50 wt. %.

A very special advantage is the use of polyethylene glycol in the stabilizer mixture. The stability of the zeolite suspension with the addition of polyethylene glycol up to 15% remains unaffected, and only above 20% of the addition of polyethylene glycol does it decrease, stabilizing the influence of the surfactant mixture. On the contrary, unexpected positive effects on the viscosity, and especially on the flow properties, are achieved by the addition of polyethylene glycol. In the range of 5 - 15% addition of polyethylene glycol, the optimal content is obtained, which takes into account stability, viscosity and flow properties.

In principle, water suspensions, except for the listed ingredients A and B and the necessary starting materials for the production of these ingredients, can be kept in relatively small quantities. If further processing of the suspension into washing and cleaning agents is envisaged, then the additionally required substances are naturally and purposefully substances suitable for the ingredients of washing and cleaning agents.

Suspensions can be produced by simply mixing their ingredients, whereby aluminum silicates can, for example, be used as such - or directly from production - already wet or in aqueous suspension. It is particularly advantageous to mix component B into aluminum silicates still wet from production, for example as a precipitate separated by filtration.

Of course, they can also be used already dried, i.e. aluminum silicates freed from adhesive moisture, which may contain bound water.

The suspension according to the invention is characterized by high stability and other advantages.

Its stabilizing effect is especially valuable for aluminum silicates with particle sizes from 1 to 30 μm. They can be pumped to allow easy handling of wet aluminum silicates. Even after longer pumping interruptions, these suspensions can be pumped again without difficulty. Due to their high stability, suspensions can be transported in ordinary tank wagons, without fear of the formation of unusable or harmful residues. Thus, these suspensions are excellent as a delivery form of aluminum silicates for delivery, for example, to manufacturers of detergents.

These suspensions according to the invention are particularly suitable for further processing into apparently dry, loose products, suitable for spraying, i.e. for the production of powdered aluminum silicates.

When feeding the aqueous suspension to the drying device, no annoying residues are formed. Furthermore, it was shown that the suspension according to the invention enables processing to a product with extremely little dust.

Due to their special stability, the suspensions according to the invention can be used as such, i.e. without further processing, with or without additives for washing, bleaching and/or cleaning, e.g. as water softeners, washing and cleaning agents and especially as mild liquid scouring agents increased suspension stability.

A particularly important application of the suspension is in the further processing into apparently dry, loose washing and cleaning agents suitable for spraying, which, in addition to the ingredients in the suspension, also contain other compounds.

The suspensions according to the invention are particularly suitable for the production of powder detergents and cleaning agents.

In the production of such products, the starting point is an aqueous, liquid solution of the previous mixture of individual ingredients and it is translated in the usual way into a loose product. The aluminum silicate defined above is used in the form of a suspension according to the invention. The suspensions according to the invention can be processed by arbitrary known procedures into solid, loose washing and cleaning agents.

In the production of powder detergents, the special procedure is to mix the suspension according to the invention - for example from a container - with at least one ingredient for washing and cleaning or bleaching, and then this mixture is converted into a powder product by an arbitrary process. It is convenient to add a complexing agent, i.e. a compound capable of complex binding and those responsible for the hardness of water, especially alkaline earth metals, such as magnesium and calcium.

In the general case, during the production of detergents and cleaning agents, the suspension according to the invention is first combined with at least one water-soluble surfactant, which does not belong to the possible components of component B.

In the production of washing and cleaning products, there are different versions.

For example, substances capable of binding crystal water can be combined with the suspension according to the invention, in a purposeful way by spraying the suspension on the compounds capable of binding crystal water, previously placed in the mixer, so that a solid, apparently dry product is obtained at the end with constant mixing.

However, it is better to mix the suspensions according to the invention as a slurry with at least one other washing or cleaning compound and subject them to a spray drying process. In addition, the surprising advantages of the suspension of these aluminum silicates are shown. Namely, it has been shown that using the suspension according to the invention in the spray drying process produces products with very little dust. The products obtained by the spray drying process show a high ability to bind calcium and crosslink well.

Detergents produced using the suspension according to the invention can be assembled in a variety of ways. In the general case, at least one dispersing agent that does not belong to the invention of the respective aluminum silicates, namely a water-soluble surfactant, is added to them. At least one other compound which acts in terms of washing, cleaning or bleaching and of an inorganic or organic nature, such as the aluminum silicate defined above, which acts as a calcium binding compound is also added. In addition, such agents may include other common substances, usually in small amounts.

Examples

The precipitate of zeolite A with stabilizer, separated by filtration, is mixed if necessary with the addition of water.

Components B and C are added as stabilizers. The degree of ethoxylation of the EO is also indicated. The zeolite A precipitate used, separated by filtration, is produced according to DE-OS 26 51 485 and has the particle spectrum specified there.

To implement the example, 50 kg of unstabilized zeolite suspension is mixed for one hour at 500 rpm with the addition of water as needed in an Ekato-Standardmix mixer.

After adding 1.5 wt. % of the stabilizer mixture is mixed for another 10 minutes at the same speed.

The cloud points of the stabilizers used are listed in Table I.

Table I.

Cloud points according to DIN 53 917 of the applied oxoalcohol ethoxylates (5 g of surfactants on 25 g of a 25% butyldialycol solution).

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Surfactants from the production process contain polyethylene glycol (PEG) in amounts of 1%. In order to check the influence of PEG on the stability and fluidity properties, PEG, with an average molecular weight of approximately 800, is added to a 1:1 mixture of both individual surfactants in such 1:1 amounts that the total PEG content is about 7% and 15% and 20 wt. %. Stability is checked after 3 days (table 2), while viscosity and flow are checked on the same day (tables 3 and 4).

Table II

Stabilization of zeolite suspension using oxoalcohol ethoxylates with C12/13-chain length (solid content in zeolite suspension: 49%).

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Homogeneity and flow were evaluated according to the school system (1 = very good, up to 5 = poor).

Table III

Viscosity measurement on stabilized zeolite suspensions at different temperatures (Measuring device Brookfield RTV, axis 4).

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Table IV

Determining the expiration time using pitcher no. 4 according to

to DIN (DIN 53 211) at 22°C.

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Claims (4)

1. An aqueous, stable suspension of a silicate, which can be pumped and which is insoluble in water, characterized in that, reduced to the total weight of the aqueous suspension, it contains A) one silicate capable of binding calcium, 0.5 to 80 wt. % of a finely distributed, synthetically produced, water-insoluble compound containing bound water (Kat2/nO)x⋅Me2O3⋅(SiO2)y (I), where Kat denotes one cation exchangeable with calcium of value n, x denotes a number from 0.7 to 1.5 Me is boron or aluminum, and y is a number from 0.8 to 6 and B) as a dispersing component, a mixture of at least two oxoalcohol-ethoxylates of formula II R-(OCH2CH2)n-OH (II), where R = C10-C15 alkyl with a degree of branching from 0 to 90% linear and 100 to 10% monobranched with methyl, where n = 3 - 5.25 mol EO in component 1, n =5.5 - 7.0 mol EO in component 2, i C) one polyethylene glycol with an average molecular weight of 200 to 2000, whereby the mass fraction of components B and C, reduced to a suspension, amounts to 0.5 to 6 wt. %. 2. Suspension according to claim 1, characterized in that component A is in a crystalline state. 3. Suspension according to claims 1 or 2, indicated by the fact that in formula I of component A, the number y is 1.3 to 4. 4. Suspension according to claims 1 to 3, characterized in that component A is zeolite A.